Nomenclature

a

wavespeed

A

cross-sectional flow area of a pipe

BM

compatibility equations parameter for method of characteristics

BP

compatibility equations parameter for method of characteristics

CD

discharge coefficient

CM

compatibility equations parameter for method of characteristics

CP

compatibility equations parameter for method of characteristics

CV

valve coefficient

CHW

Hazen-Williams factor

D

diameter of a pipe

E

modulus of elasticity

e

pipe wall thickness

f

friction factor

fT

turbulent friction factor (used by Crane, 1988)

fL

laminar friction factor

fTr

transition friction factor

F

error value in mass balance

FB

Dimensionless pump torque parameter (see Four Quadrant Model Overview)

FH

Dimensionless pump head parameter (see Four Quadrant Model Overview)

g

gravitational constant

H

head

HGL

hydraulic gradeline (piezometric head)

I

moment of inertia of pump and entrained liquid

J

Jacobian matrix

K

loss factor

K

constant for Power Law fluid

KB

liquid bulk modulus of elasticity

Ksprinkler

fire sprinkler loss factor

L

length of a pipe

mass flow rate

n

general constant

n

constant for Power Law fluid

N

pump synchronous speed (rpm)

P

pressure, static

Po

pressure, stagnation

Pw

wetted perimeter

P

power

Q

volumetric flow rate

r

radius

r

relaxation

R, R

resistance or gas constant

Rc

coefficient of rigidity

Re

Reynolds Number

s

pump speed

SB

parameter as derived from conservation of mass

SC

parameter as derived from conservation of mass

Sy  

yield stress

t

time

T

torque on pump

v

pump flow ratio to reference

V

velocity

V

volumex        distance along pipe centerline

z

elevation

α, μ, θ

angle

α

pump speed ratio

β

diameter ratio

β

torque ratio

λ

method of characteristics multiplier

η

efficiency

ν

kinematic viscosity

ε

roughness

ω

pump speed

ρ

density

μ

dynamic viscosity


Subscripts

i

junction or pipe station at which solution is sought

j

junctions with pipes connecting to junction i

R

rated conditions for a pump, usually BEP

o

stagnation

infinity, far away, ambient

new

current time for computation

old

most recent time for computation